Abstract: The constructed plasmid containing aglA gene was transformed into Escherichia coli BL21 Gold （DE3） to induce its successful expression, and the transglucosidase was synthesized to catalyze the production of α-arbutin. Then the transglucosidase was extracted and purified by ultrasonic crushing technique and nickel ion chromatography column and fixed by sodium alginate-gelatin mixture so that it could be reused. The optimum immobilization conditions were as follows： A mixture of colloid dissolved in pH 7 with 3.0% sodium alginate and 3.0% gelatin was prepared. The solution was titrated at a height of about 45 cm and pre-cooled at 4 ℃ by 300 g/L calcium chloride solution and immobilized for 20 min. After washing, calcification was performed at -20 ℃ for 50 min to obtain immobilized beads with a diameter of 3.97 mm and a mass of 0.311 g.

Key words: induced expression, α-arbutin, transglucosidase, immobilization